With the progress of display technology, the display is developed to provide various functions. By wired or wireless transmitting technique, the display device can display the corresponding picture for the user according to the image data provided by the image source device. The multi-pictures display function makes the display device capable of showing multiple pictures of multiple signal sources together on the single display device, and hence the user can view multiple pictures or watch multiple programs through the single display device at the same time.
In order to display multiple pictures together on the display device, the current method in which the multiple image source devices are respectively connected to the single display device by the user is utilized, such that the display device can receive multiple image sources and display multiple pictures together by using display panel thereof. Generally, the display device may inform these image source devices about its specification (e.g. the monitor resolution and the refresh rate, etc) and the model type when the display device is connected to these image source devices. On the other hand, the image source device may generally record the specification and the model type of the display device to provide the image data according to the monitor resolution supported by the display device. However, when the display device performing the multi-pictures function, the display region of the display panel may be divided into multiple display areas to respectively display the pictures of these image source device. In this situation, the scaler of the display device needs to perform additional scaling processing to the received image data when the image source device still provides the image data based on the monitor resolution informed by the display device or the resolution which hasn't been adjusted manually, which easily causes that the displayed pictures are distorted or are not as good as the user expected.